Technical Bulletin #166 Oligonucleotide Separation on ZirChrom -SAX Absorbance () 5 45 4 35 3 25 2 15 1 5 Analytes Poly (A)- hydrolysate 2 4 6 8 1 12 Time (Minutes LC Conditions Column: ZirChrom -SAX, 5 mm x 4.6 mm i.d. Mobile Phase: A:.2 M potassium phosphate dibasic and.4 M NaCl at ph 8.5 B:.2 M potassium phosphate dibasic and 1. M NaCl at ph 8.5 Gradient: 5 to 95 % B over 9 minutes Flow rate: 1. ml/min. Temperature: 1 ºC Detection: 254 nm Injection: 25 µl
Technical Bulletin #214 Trace Iodide Separation on ZirChrom -SAX Nitrate Peak Analytes 2M nitrate sample matrix and Iodide 3 5 1 ppm I- 25 2 4 3 2 1ppm I- 15 1 1 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 min 5 1 2 3 4 5 6 LC Conditions Column: ZirChrom -SAX, 5 x 4.6 mm Mobile Phase: 25mM ammonium phosphate, 275mM NaCl at ph 8. Flow rate: 1. ml/min. Temperature: 3 C Detection: 226 nm
Technical Bulletin #22 Fertilizer Plant Effluent Ions on ZirChrom -SAX 16 1 2 Analytes 1 - Cyanate (1. mg/ml) 2 - Nitrate (.2 mg/ml) 14 12 1 8 6 4 2 1 2 3 4 5 6 7 min LC Conditions Column: ZirChrom -SAX, 15 x 4.6 mm Mobile Phase: 25mM sodium fluoride, 175mM sodium chloride at ph 1. Flow rate: 1. ml/min. Temperature: 3 C Detection: 25 nm Injection Vol.: 5 ul
High Performance Biomolecule Separations Using Zirconiabased Ion Exchange Phases Silica and polymer-based phases used for the separation of biomolecules have traditionally suffered from such limitations as substrate instability in alkali media and shrinking/swelling of the particles upon changes in mobile phase composition. The extraordinary chemical and physical stability of zirconia-based phases allows much greater flexibility in method development for biomolecules. This note shows a separation of a polynucleotide hydrolysate using a ZirChrom -SAX. The long-term reliability of an HPLC method depends greatly on the ruggedness of the stationary phase. In bonded silicas, an Si-O-Si bond is used to attach functional groups to the silica surface. It is well known that this bond is subject to chemical attack, especially at low ph. The silica itself dissolves readily in aqueous mobile phases at high ph. Even sophisticated silica bonding technologies have not solved this problem 1. The basic instability of bonded silicas causes retention drift, short column life, and frequent replacement of the column and re-qualification of the HPLC system. This is expensive both in terms of actual expenditures and in terms of lost productivity. Zirconia-based Phases for Ion Exchange Chromatography Porous zirconia coated with polyethyleneimine (PEI) has been shown to be very useful for the separation of nucleosides, nucleotides, oligonucleotides, oligodeoxynucleotides and proteins 2. The PEI coating can be crosslinked with a hydrophobic crosslinker and subsequently quaternarized to produce the stationary phase known as ZirChrom -SAX which exhibits a mixed-mode characteristic of both reversed-phase and ion-exchange retention mechanisms. Because of the mixed-mode characteristic of the phase, temperature can be used as an effective tool in method development to selectively moderate the contributions of the ionexchange and reversed-phase retention mechanisms to the overall retention. Technical Bulletin #267 Clayton V. McNeff, Peter W. Carr A hydrolyzed sample of Poly-G (oligonucleotide) was separated at elevated temperature using a ZirChrom -SAX column. The separation conditions were as follows: Column: 4.6 mm x 5 mm ZirChrom -SAX Mobile Phase: Gradient elution from 5-95% B A:.2 M potassium phosphate dibasic and.4 M NaCl, ph 8.5 B:.2 M potassium phosphate dibasic and 1. M NaCl @ ph 8.5 Temperature: 1 o C Injection Vol.: 25 µl Flow rate: 1. ml/min. Detection: UV at 254 nm Results The chromatogram below illustrates the capability of a zirconiabased ion-exchange phase to resolve nucleotide oligomers in a hydrolysate of poly-g. The separation is performed in a phosphate buffer at 1 o C, further demonstrating the extraordinary chemical stability of the stationary phase. References (1) J. J. Kirkland et. al., Anal. Chem. 61, 2-11 (1989). (2) C. McNeff et al., Anal Chem. 67, 235-2353 (1995). 2 4 6 8 1 12 minutes Figure 1: Separation Poly-G Hydrolysate 617 Pierce Street, Anoka, MN 5533 Visit www.zirchrom.com for more application notes using ultrastable, high efficiency DiamondBond columns from ZirChrom.
Analysis of Inorganic Sulfate in Water with ZirChrom -SAX Dr. Clayton McNeff, ZirChrom Separations Dwight Stoll, ZirChrom Separations Technical Bulletin #274 Scientists at a leading cattle feed additive company, SarTec Corporation, needed a robust, linear method for the quantification of inorganic sulfate in water. ZirChrom method developers found the solution on ZirChrom -SAX. The new method provides quantitation of inorganic sulfate (Na 2 SO 4 ) in under 3 minutes by indirect UV detection (Figure 1). This method of sulfate quantitation is reproducible, fast and produces a very linear standard curve (figure 2). The ZirChrom- SAX method allowed scientists at SarTec to quickly determine the sulfate concentration of water samples before and after experimental procedures to remove sulfate anions. 5-5 Peak Area 2 15 1 5 y =.8321x R 2 =.9996-1 -15 2 ppm 5 1 15 2 25-2 Sulfate Concentration (ppm).5 1 1.5 2 2.5 Figure 1: Analysis of Inorganic Sulfate in Drinking Water. Consumption of water with high levels of sulfate anion has been shown to lead to higher incidence of PEM (polioencephalomalacia) in beef cattle (1). The scientists at SarTec needed a way to reliably quantitate the amount of sulfate in water before they could test their hypothesis for its removal. A set of sulfate standards was made through serial dilution. Four replicates were performed for each of the concentrations. Column: 4.6 mm x 15 mm ZirChrom-SAX Mobile Phase: 2mM ethylenediaminetetra(methylphosphonic) acid (EDTPA), 2mM 2-(N-morpholino)ethane sulfonic acid (MES), 5mM Sodium Chloride Injection Vol.: 1 ul Pressure Drop: 195 bar Detection: UV at 22 nm Flow Rate: 2.5 ml/min Temperature: 5 ºC min Figure 2: Standard Curve for Sulfate Analysis on ZirChrom -SAX Dr. Peter Greuel of SarTec corporation said Not only is the analysis fast but so was the method development process. We are extremely happy with the results we ve seen and look forward to working with ZirChrom in the future. References (1) J.J. Wagner, Continental Beef Research, Lamar, CO; G.H. Loneragen and D.H. Gould, Colorado State University, Ft. Collins, CO. Acknowledgments Dr. Peter Greuel, General Manager, SarTec Corporation 617 Pierce Street, Anoka, MN 5533 Visit www.zirchrom.com for more application notes using ultrastable, high efficiency ZirChrom columns.
Green Analysis of Diet Soft Drinks Containing Caffeine and Aspartame Dwight Stoll and Dr. Clayton V. McNeff Technical Bulletin #278 The popularity of diet soft drinks containing aspartame requires the analysis of thousands of samples for quality control purposes each year. These analyses are typically carried out with some fraction of organic modifier in the eluent, leading to the generation of thousands of gallons of hazardous organic waste. This note shows the green analysis of several commercial diet soft drinks in combination with a 1% water mobile phase. The analysis of caffeine, aspartame, and benzoate from diet soft drinks is not especially challenging, as one can find this type of application in nearly every column manufacturers catalog. However, the typical conditions employed for reversed-phase separations of these compounds involves anywhere from 5-25% organic modifier. Whether this organic component of the eluent is methanol or acetonitrile, the added handling costs associated with either recycling or disposing of the used eluent can often be a major portion of the total analysis cost. The extraordinary chemical and thermal stability of zirconiabased stationary phases allow the chromatographer to use a wide range of mobile phases and column temperatures to develop rapid separation methods while retaining method robustness. ZirChrom -SAX is an anion-exchange material that is built on microporous zirconia and contains a substantial amount of hydrophobic cross-linker that imparts mixed-mode ion-exchange/reversed-phase characteristics. The separation of caffeine, aspartame, and benzoate shown here in a 1% aqueous mobile phase demonstrates the capability of the mixed-mode column to separate these compounds of wide-ranging chemical properties. The 1% aqueous mobile phase containing dilute amounts of phosphate and carbonate is completely environmentally friendly, eliminating the need for costly handling and disposal of the eluent. Finally, the thermal stability of the ZirChrom -SAX material allows the separation to be carried out at 5 o C to decrease overall analysis time. Visit www.zirchrom.com for more application notes using ultrastable, high efficiency ZirChrom columns. Samples of several commercial soft drinks were filtered with.45 µm filters and injected neat on a ZirChrom -SAX column using the following conditions. Column: 3. mm x 1 mm ZirChrom -SAX Mobile Phase: 1mM Ammonium phosphate, 5mM Ammonium carbonate, ph 6.6 Flow rate: 1. ml/min. Temperature: 5 o C Injection Vol.: 5. µl Pressure Drop: 25 bar Detection: UV at 21 nm The separation is shown in Figure 1. Under these conditions, the separation of caffeine, aspartame, and benzoate is achieved with good peak shape and baseline resolution, in under 4 minutes. Similar separations are obtained for samples of 5 different diet soft drinks indicating that this is a widely applicable method for diet soft drink analyses. 14 12 1 8 6 4 2 1 2 Diet Pepsi TM Diet Coke TM Diet Sprite TM Diet Dr. Pepper TM Diet Mountain Dew TM 1 2 3 4 5 6 Minutes Figure 1. Analysis of several diet soft drinks. 1=Caffeine, 2=Aspartame, 3=Benzoate ZirChrom columns combine the high efficiency usually associated with silica columns with complete chemical and thermal stability. 3 617 Pierce Street, Anoka, MN 5533
Water-Soluble Vitamin Analysis on ZirChrom -SAX Dr. Bingwen Yan and Dr. Clayton McNeff Technical Bulletin #35 Traditionally the analysis of water-soluble vitamins by reversed-phase HPLC has been complicated by the lack of retention for these compounds on conventional silica C18 columns. Other analytical approaches, such as ionpair chromatography, have also failed to yield successful and reproducible results. Here we demonstrate efficient baseline resolution of six water-soluble vitamins in six minutes using a ZirChrom -SAX column. This method can be combined with ZirChrom s ProTain In-Line Protein Removal System for the analysis of these compounds in biological samples. In this application note we focus on the HPLC analysis of Vitamin C and five B-complex vitamins; Vitamin B 1 (thiamine), Vitamin B 2 (riboflavin), Vitamin B 3 (nicotinic acid form), Vitamin B 3 (nicotinamide form), and Vitamin B 6 (pyridoxine). All of these vitamins are water-soluble. Chromatographers oftentimes struggle in their attempts to analyze water-soluble vitamins by HPLC. Many watersoluble vitamins are very polar. Thiamin (Vitamin B 1 ), pyridoxine (Vitamin B 6 ) and ascorbic acid (Vitamin C), for example, show almost no retention on conventional C18 columns. Reversed-phase analytical methods employing ionpair reagents have been offered as a potential solution to this problem, but these methods tend to suffer from column-tocolumn reproducibility problems due to the somewhat unpredictable way ion-pairing reagents interact with the silica surface and the bonded phase. In this technical bulletin we present a unique method for the analysis of water-soluble vitamins using a ZirChrom -SAX HPLC column. ZirChrom -SAX, an anion exchange material, is polyethleneimine-coated zirconia containing a substantial amount of hydrophobic cross-linker which imparts both ion-exchange and reversed-phase characteristics. The mixed mode retention characteristics of the ZirChrom -SAX column create the unique selectivity ideal for this application (Figure 1). For the analysis of water-soluble vitamins in serum, or other samples containing biological matrices, we recommend the addition of the ProTain In-Line Protein Removal System; consisting of one guard holder (part# 85--2) and a set of three ProTain inserts (part# PT1-246). Please see technical bulletins #275 and #291 for further information on the use of ZirChrom s ProTain In-Line Protein Removal System. Six water-soluble vitamin standards were prepared in an aqueous solution and injected on a ZirChrom -SAX column. The separation conditions are as follows. Column: ZirChrom -SAX, 15 x 4.6 mm i.d. (part number: ZR6-1546) Mobile Phase: 5 mm Ammonium dihydrogenphosphate, ph 4.5 Flow rate: 1. ml/min. Temperature: 3 o C Injection Vol.: 5. µl Detection: UV at 254 nm The separation is shown in Figure 1. Under these conditions the separation of Vitamin C and the four B-complex vitamins is achieved, with good peak shape and baseline resolution, in 6 minutes. 1 2 3 4 1 2 3 4 5 6 min. Figure 1. Analysis of Water-Soluble Vitamins. 1=Thiamine (Vit. B 1 ), 2=Pyridoxine (Vit. B 6 ), 3= Nicotinamide (form of Vit. B 3 ), 4=Riboflavin (Vit. B 2 ), 5=Nicotinic acid (form of Vit. B 3 ), 6=Ascorbic acid (Vit. C) ZirChrom columns combine the high efficiency usually associated with silica columns with complete chemical and thermal stability. 617 Pierce Street, Anoka, MN 5533 5 6
LC/MS Compatible Separation of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) on ZirChrom -SAX Dr. Bingwen Yan and Dr. Clayton McNeff In this application note we demonstrate the unique selectivity and versatility of the ZirChrom -SAX column. The ZirChrom -SAX column is a strong anion-exchanger that has a hydrophobic character to the stationary phase. The mixed-mode retention characteristic of the crosslinked polyethyleneimine-coated strong anion exchanger, ZirChrom SAX, enables an LC/MS-compatible isocratic separation of four non-steroidal anti-inflammatory drugs (NSAIDs) in less than 4 min. Technical Bulletin #37 ammonium formate buffer to resolve non-steroidal antiinflammatory drugs quickly using isocratic conditions (Figure 2). Four non-steroidal anti-inflammatory drugs were prepared in an aqueous solution and injected on a ZirChrom -SAX column. The separation conditions are as follows. Column: ZirChrom -SAX, 5 x 4.6 mm i.d. (part number: ZR6-546) Mobile Phase: 8/2 ACN/15 mm ammonium formate, ph=4. (adjusted with formic acid) Flow rate: 1. ml/min. Temperature: 35 o C Injection Vol.: 1. µl Detection: UV at 254 nm 1 Figure 1: Compound structures Traditional silica methods for the separation of acetaminophen, ibuprofen, naproxen (common pain relievers/anti-inflammatories) and ketoprofen (used to control joint pain and swelling associated with rheumatoid arthritis) often require complex gradients and mobile phases to achieve satisfactory selectivity. NSAIDs have a carboxylate moiety, which makes them a effective Lewis base (Figure 1). It is well know that Lewis bases can interact strongly with zirconia-based columns, sometimes resulting in poor peak shapes. The strength of different common Lewis bases on zirconia has been previously reported (1). Although NSAIDs carboxylic acid moiety and formate are very near each other in elutropic strength, keeping the ph of the separation near the pka of NSAIDs carboxylic acid moiety increases the likelihood that it is protonated and thus will be efficiently displaced from the Lewis acid sites on zirconia by the smaller and more acidic formate anion. The resulting innovative approach uses the mixed-mode retention characteristics of the zirconia-based strong anion exchange phase, ZirChrom -SAX, and a LC/MS-compatible 8 6 4 2 1 2 3 ZirChrom columns combine the high efficiency usually associated with silica columns with complete chemical and thermal stability. References (1) Blackwell, J. A.; Carr, P. W. Journal of Liquid Chromatography 1991, 14, 2875-2889. 2 Figure 2. Separation of NSAIDs: 1=Acetaminophen, 2=Ibuprofen, 3=Naproxen, 4=Impurity, 5=Ketoprofen. min 617 Pierce Street, Anoka, MN 5533 3 4 5
Isolation of Glyphosate in a Broad Leaf Herbicide using ZirChrom-SAX Clayton McNeff, Ph.D. and Dwight Stoll Technical Bulletin # 32 Attempts at isolation using silica based columns of glyphosate, and an important process impurity, peak C, in a broad leaf herbicide are often hindered by lack of resolution, poor peak shape and short column lifetime. ZirChrom -SAX provides baseline resolution of all process components employing an aqueous isocratic method with good peak shape and excellent column lifetime. All components are well separated with good peak shape including peak D isomers and the peak C impurity peak. Figure 1: Structure of glyphosate Glyphosate [N-(phosphonomethyl) glycine] is a regulated, broad spectrum, postemergence herbicide, sold under the trade names Roundup (Monsanto Co., St. Louis, MO) and Rodeo (Dow AgroSciences, Indianapolis, IN)(1). Process testing requires the isolation of glyphosate and its impurities. Although selectivity for this analysis is improved using phosphate buffer and high ph employing these conditions may result in very short column lifetimes for silica based ion exchangers. The unique selectivity and superior stability of the ZirChrom -SAX column allow method developers to choose the mobile phase that results in optimum selectivity without compromising column lifetime. A broad leaf herbicide was diluted 1:1 in mobile phase and separated at 3ºC using a ZirChrom -SAX column. The separation conditions were as follows: Column: ZirChrom -SAX, 15 mm x 4.6 mm i.d. (Part Number: ZR6-1546) Mobile Phase: 2mM Ammonium Phosphate, ph 8.5 Temperature: 3 ºC with Metalox 2-C column heater Flow Rate: 1. ml/min. Injection Vol.: 5 µl Detection: UV at 254 nm Figure 2: 1=Isopropylamine 2=Unknown 3=Glyphosate 4,5=peak D isomers 6=peak C (Impurity). This method can be tailored to your specific application needs. ZirChrom technical support can help to optimize and transfer this method to your site. Please contact ZirChrom technical support at or for details. ZirChrom phases offer unique selectivity, high efficiency, and excellent chemical and thermal stability. References (1) Farm Chemicals Handbook; Berg, Gordon L. Ed.; Meister: Willoughby, OH, 1989; p C147. 617 Pierce Street, Anoka, MN 5533 Visit www.zirchrom.com for more application notes using ultrastable, high efficiency ZirChrom columns.
Green Separation of Caffeine, Benzoate and Sorbate in Energy Drinks Merlin Bicking, Ph.D. and Kelly S. Johnson ACCTA and Technical Bulletin # 339 In this application we examine the superior selectivity of the ZirChrom -SAX phase for caffeine, benzoate and sorbate in energy drinks. Figure 2 clearly demonstrates that the neutral condition on a silica C18 column has too little retention of these compounds and that the acidic condition does not separate sorbate and benzoate. In comparison, the ZirChrom -SAX column separates all three of the compounds in siz minutes using isocratic conditions and UV detection. Benzoate Caffeine Sorbate C18: ph 6, 5% Acetonitrile C18: ph 2, 5% Acetonitrile Figure 1: Structures of caffiene, sorbate and benzoate. Benzoate and sorbate are used as preservatives in many foods, including energy drinks. Traditionally the analysis of these compounds using silica C18 phases is hindered by low retention and poor selectivity. ZirChrom Green Mobile Phase The unique multimodal selectivity of Zirchrom -SAX can take advantage of differences between the ionized forms, allowing for both ion exchange and reversed phase modes of separation. Here we present an isocratic method that provides excellent selectivity and retention, resulting in 6 minute baseline resolution of caffeine, sorbate, and benzoate using UV detection at 23 nm. For comparison, we present the analysis of the same compounds using both neutral and acidic conditions on a leading silica C18 column. Three compounds in a common energy drink caffeine, sorbate and benzoate, were separated in 6 minutes using a ZirChrom -SAX column. The separation conditions were as follows and as noted in Figure 2: Column: ZirChrom -SAX, 1 mm x 4.6 mm i.d. (Part Number: ZR6-146) Mobile Phase: 1mM NH 4 H 2 PO 4 + 5 mm NH 4 CO 3 Temperature: 5 ºC Flow Rate: 1.5 ml/min. Injection Vol.: 5 µl Detection: UV at 23 nm Figure 2: 1 =Caffeine, 2 = Sorbate, 3=Benzoate This method can be tailored to your specific application needs. ZirChrom technical support can help to optimize and transfer this method to your site. Please contact ZirChrom technical support at or for details. ZirChrom phases offer unique selectivity, high efficiency, and excellent chemical and thermal stability. 617 Pierce Street, Anoka, MN 5533 Visit www.zirchrom.com for more application notes using ultrastable, high efficiency ZirChrom columns.